#include <stdio.h>
int main(void) 
{
	int n;
	int factorial(int n);
	 
	scanf("%d",&n);
	printf("%d\n",factorial(n));
	 
	return 0;
} 

int factorial(int n)
{ 
    int i,fact;
    
    fact=1; 
    for(i=1;i<=n;i++) 
    { 
       fact=fact*i;
	} 
	
	return fact;
}
